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→CREATE TABLE / DROP TABLE
== Install ==
==Install==
=== Debian/Ubuntu ===
===Debian/Ubuntu===
sudo apt-get update
sudo apt update
sudo apt-get install postgresql postgresql-contrib
sudo apt install postgresql postgresql-contrib
== Remote access ==
==Data directory==
<code>/var/lib/postgresql</code>
<br />
==Remote access==
1.- Modify pg_hba.conf to add Client Authentication Record<br />
1.- Modify pg_hba.conf to add Client Authentication Record<br />
To allow remote access edit: /etc/postgresql/9.4/main/pg_hba.conf
To allow remote access edit: /etc/postgresql/9.4/main/pg_hba.conf
Example:
Example:
<nowiki> TYPE DATABASE USER CIDR-ADDRESS METHOD
<nowiki> TYPE DATABASE USER CIDR-ADDRESS METHOD
# IPv4 local connections:
# IPv4 local connections:
host all all 127.0.0.1/32 md5
host all all 127.0.0.1/32 md5
# IPv6 local connections:
# IPv6 local connections:
host all all ::1/128 md5</nowiki>
host all all ::1/128 md5</nowiki>
2.- Change the Listen Address in postgresql.conf
2.- Change the Listen Address in postgresql.conf
sudo -i -u postgres -H nano /var/lib/pgsql/data/postgresql.conf
sudo -i -u postgres -H nano /etc/postgresql/9.4/main/postgresql.conf
set: listen_addresses = '*'
set: listen_addresses = '*'
==Crate users==
From postgres shell account type:
createuser --interactive
To change the user password:
ALTER USER postgres WITH ENCRYPTED PASSWORD 'P@$$worD1';
==Create database==
From the postgres user shell:
createdb test1
==CREATE TABLE / DROP TABLE==
<nowiki>
CREATE TABLE table_name (
column_name1 col_type (field_length) column_constraints,
column_name2 col_type (field_length),
column_name3 col_type (field_length)
);
DROP TABLE table_name;</nowiki>
=== Drop all tables ===
<syntaxhighlight lang="sql">
DO $$ DECLARE
r RECORD;
BEGIN
FOR r IN (SELECT tablename FROM pg_tables WHERE schemaname = 'public') LOOP
EXECUTE 'DROP TABLE IF EXISTS public.' || quote_ident(r.tablename) || ' CASCADE';
END LOOP;
END $$;
</syntaxhighlight>
==List users==
\du
==List databases==
\list or \l
==List tables==
\d
\dt
==ADD, QUERY, DELETE from table==
Add
INSERT INTO table_name (column_name1, column_name2, column_name3, column_name4)
VALUES ('value1', 'value2', 'value3', 'value4');
Query
SELECT * FROM table_name;
Delete
DELETE FROM table_name WHERE column_name = 'value1';
Update
UPDATE table_name SET column_name1= 'value32' WHERE column_name2 = 'value2';
==ALTER TABLE==
ALTER TABLE table_name ADD column_name5 date;
ALTER TABLE table_name DROP column_name5;
==Dump database==
<syntaxhighlight lang="bash">
g_dump -C -h localhost -U scrapy scrapydb > scrapydb_dump.sql
</syntaxhighlight>
===Dump one database to another database===
<syntaxhighlight lang="bash">
g_dump -C -h localhost -U scrapy scrapydb | psql -h ec2-54-77-228-53.eu-west-1.compute.amazonaws.com -U scrapy scrapydb
</syntaxhighlight>
==Import .sql dump file==
psql databasename < data_base_dump
pg_restore -h localhost -U postgres -d mapper -1 /tmp/mapper_before_refactoring_2018_11_13.sql
==Error creating UTF-8 database==
02:39:35: Error: ERROR: new encoding (UTF8) is incompatible with the encoding of the template database (SQL_ASCII)
SUGERENCIA: Use the same encoding as in the template database, or use template0 as template.
==Create user, database and password==
*Create the user<br />
postgres@hostname:~$ createuser
Enter name of role to add: username
Shall the new role be a superuser? (y/n) n
Shall the new role be allowed to create databases? (y/n) n
Shall the new role be allowed to create more new roles? (y/n) n
CREATE ROLE
*Create the DB
postgres@hostname:~$ createdb databasename
CREATE DATABASE
postgres@hostname:~$
*Grant access for the user to the DB
postgres@hostname:~$ psql
postgres=# alter user username with encrypted password 'password';
ALTER ROLE
postgres=# grant all privileges on database databasename to username;
GRANT
postgres@hostname:~$
Fix:
<nowiki>update pg_database set datallowconn = TRUE where datname = 'template0';
\c template0
update pg_database set datistemplate = FALSE where datname = 'template1';
drop database template1;
create database template1 with template = template0 encoding = 'UTF8';
update pg_database set datistemplate = TRUE where datname = 'template1';
\c template1
update pg_database set datallowconn = FALSE where datname = 'template0';</nowiki>